It is known that small domestic rodents are usually hosted inside cages provided with at least one transparent wall which allows the observation of their particularly amazing movements, when the cage is provided with optional components such as slides, small staircases, wheels or whatever else could the animal need to perform physical activity.
The cage also comprises dispensers for food and water, as well as resting areas where to leave the small rodent during the whole day with the exception of the few moments required for the regular cleaning and maintenance.
At present, cages for small domestic rodents are made in a single block and with variable dimensions in relation to the number and the size of the animals to be hosted.
Cages are usually provided of large apertures to allow an easy extraction or insertion of the animals as well as their efficient cleaning.
Usually such apertures are closed by means of covers provided with openings or slits for the aeration of the inner part of the cage.
A drawback is constituted by the fact that small cages are not modular and need to be changed with larger ones when it is desired to increase the number of the animals.
Another drawback is constituted by the fact that cages of large dimensions are not always really appropriate to the domestic room in which they should be included and further, they can hardly be moved or displaced due to their large encumbrance.
A further drawback of the cages with higher capacity relates to the fact that they are difficult to clean, being divided in several portions or compartments with fixed walls which are in same cases quite difficult to be reached from the outside.
Document EP-A-0744122 discloses an animal rearing cage and a framework to which a plurality of side plates for together forming the periphery of the animal rearing cage are detachably attached.
Document U.S. Pat. No. 5,950,566 discloses a cage including two or more movable walls that can restrain an animal in two or more dimensions. the cage includes telescopic or movable planar surfaces, one preventing an animal's lateral movement, and another preventing vertical movement.
Document U.S. Pat. No. 5,247,901 discloses a containment system for animal microbiological isolation containment including a plurality of two room suites combined into two suite containment units, selectively separable adjoining exercise runs for individual and group isolation, the suites being constructed of transparent, glass panels and and satinless steel.
Document U.S. Pat. No. 4,036,177 discloses an animal confining and housing device having a wheel supported carriage with a plurality of two sets of vertically spaced and parallel guide members thereon.